JPH0223794Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a tension pulley device for a fan belt of an engine.

(Prior art and its problems) In a conventional tension pulley device, for example, a tension arm is rotatably supported on an engine, and the arm is biased by a tension spring to apply tension to the fan belt.

However, when the rotation arm is biased by a tension spring, the initial tension when tensioning the belt varies depending on the length of the belt. Furthermore, it is impossible to adjust the tension due to the elongation of the belt during use. Further, during operation, belt vibration occurs both in the direction in which the tension spring is pulled and in the direction in which it is returned, resulting in increased belt vibration and shortened belt life. On the other hand, if the tension pulley is fixed at a desired position without using a spring or the like,
It is difficult to provide an automatic engine stop mechanism when the fan belt breaks.

The applicant of this application has previously developed a tension pulley device as disclosed in Utility Model Application No. 158938/1983 (see Japanese Utility Model Application No. 60/65329) as a device to solve the above-mentioned problems. Problems remain.
In other words, if the tension pulley, fan pulley, and drive pulley are misaligned due to manufacturing errors, for example, the tension pulley may bend in the direction of arrow R or arrow R' in Fig. When the pulley becomes unable to rotate or the belt breaks, the tension pulley may not move in the direction of arrow A.

(Purpose of the invention) This invention is based on the above-mentioned Utility Application No. 58-158938
The purpose of this invention is to improve the device disclosed in Japanese Patent No. 65329 (see Japanese Patent Publication No. 65329) to prevent the vibration of the tension arm from swinging in a direction perpendicular to the axis thereof.

(Means for achieving the object) In order to achieve the above object, the present invention fixes a pulley support shaft to the distal end side of a tension arm having a shaft bolt portion, and attaches the tension pulley to the pulley support shaft. The bolt shaft side part of the tension arm is supported by the support bracket so as to be slidable in the lengthwise direction of the shaft bolt part, and a spring receiving nut is screwed into the shaft bolt part, and the tension arm is mounted between the nut and the bracket. A compression spring is compressed to apply tension to the fan belt, and a stopper for setting the initial tension is placed to compress the spring with the nut until the nut is locked to the stopper. A steady rest guide that is connected to the engine stop device and configured so that the engine is stopped by the restoring force of the spring when the belt breaks, and prevents the tension arm from swinging in the direction perpendicular to the axis of the pulley support shaft side. The mechanism is installed on the engine wall such as a bracket or cylinder body.

(Embodiment) In FIG. 4 showing a front view of an engine equipped with a pulley device according to the present invention, a drive pulley 1 with a flywheel, a fan pulley 2, and a tension pulley 3 are arranged on the front of the engine 20. A fan belt 5 is stretched across the pulleys 1, 2, and 3. The drive pulley 1 is fixed to a crankshaft 6, and the fan pulley 2 is fixed to a fan shaft 8 of a cooling fan 9. Moreover, the three pulleys 1, 2, and 3 are arranged in the same plane (the plane of the paper in FIG. 1) in principle.

In FIG. 1, which is an enlarged sectional view of FIG. 4, the tension pulley 3 is rotatably supported on a pulley support shaft 12 via a bearing 13.
2 is inserted into the tension arm 11, and a nut 14 is screwed into the tip thereof, and is fastened to the arm 11 by the nut 14. The tension arm 11 has a shaft bolt portion 1 perpendicular to the pulley support shaft 12.
1a, and the shaft bolt portion 11a is inserted into the insertion hole 15 of the support bracket 15 so as to be movable in the longitudinal direction of the shaft bolt portion. Bracket 15
has a bottom portion 15a perpendicular to the shaft bolt portion 11a, a side portion 15b parallel to the shaft bolt portion 11a, and a bent portion 15c at the tip of the side portion 15b.

The bent portion 15c is formed perpendicularly to the tension arm 11, and is formed in the guide hole (notch) 1.
7, and a guide portion 18 for preventing the arm 11 from steadying is fixed to the distal end surface of the bent portion 15c. The tip of the tension arm 11 is inserted into the guide hole 17, and the periphery of the guide hole 17 and the guide portion 18 restrict the vibration of the tension arm 11 in a direction perpendicular to its axis. Support bracket 15
The side portion 15b of is fixed to the cylinder body 20a with a bolt 19. A spring receiver washer 21 is fitted into the shaft bolt portion 11a, and a spring receiver nut 22 is screwed into the shaft bolt portion 11a, and a compression spring 24 for tension is compressed between the spring receiver washer 21 and the bottom portion 15a of the bracket 15. At the same time, a cylindrical initial tension setting stopper 25 is arranged. The stopper 25 is arranged on the outer peripheral side of the spring 24 and also serves as a guide for the spring 24. The nut 22 is tightened through the spring receiver washer 21 until it is locked to the stopper 25, and the spring 24 is tightened to the stopper 25.
It is compressed to the same length as 5.

The length of the stopper 25 and the elastic force of the spring 24 are:
The setting is such that when the spring 24 is compressed to the same length as the stopper 25, an optimal initial tension is applied to the belt 5.

In FIG. 2, an inner wire attachment fitting 35 is fixed to the shaft bolt portion 11a with a nut 36, and an inner wire 29 is attached to the attachment fitting 35.
The tip of the head is engaged. On the other hand, bracket 15
One end of an outer wire 28 is fixed to the bottom 15a of the outer wire 28 with a nut 27. Inner wire 2
9 extends parallel to the shaft bolt portion 11a and passes through the outer wire 28, and is an engine stop device;
For example, it is connected to a regulator lever 33 of a speed governor, and by pulling the inner wire 29 in the direction of arrow A, the engine 20 can be stopped.

In FIG. 3, the tension arm 11 has a rectangular cross-section, and therefore the guide hole 17 also has a rectangular shape corresponding to the cross-section of the tension arm 11.

Next, the belt tensioning work and operation will be explained. When applying initial tension to the fan belt 5, use the nut 2.
2 is tightened until it contacts the stopper 25 via the spring seat 21, and then the nut 22 is further tightened, for example, 2 to 3 turns to hold the spring 24 at the same length as the stopper 25. This allows the belt 5 to be tensioned with an appropriate initial tension. During engine operation, the compression of the spring 24 due to engine vibration is regulated by the stopper 25, and the belt 5 does not swing in a direction that compresses the spring 24.

Furthermore, even if the pulleys 1, 2, and 3 shown in FIG. 4 are misaligned due to manufacturing errors, the regulating action of the guide portion 18 will prevent the tension arm 11 from swinging in the right angle direction, for example in the direction of arrow R or arrow R'. Directional vibrations, etc. are reliably controlled. Therefore, an accident in which the tension pulley 3 becomes unable to rotate due to the bending of the arm 11 can be prevented.

When the belt 5 breaks, the tension arm 11 moves in the direction of arrow A due to the restoring force of the spring 24, the inner wire 29 is pulled, the regulator lever 33 moves to the engine stop position, and the engine stops. do.

(Another embodiment) (1) In the embodiment shown in FIG. 5, a round bar-shaped guide portion 18' is formed at the tip of the pulley support shaft 12, and a guide hole 17' is formed at the side portion 15b of the bracket 15. A guide portion 18' is fitted into the guide hole 17'. Inner peripheral surface of guide hole 17' and guide part 1
The contact with the outer peripheral surface of the tension arm 11 prevents the tension arm 11 from swinging in a direction perpendicular to its axis.

(2) In the embodiment shown in FIG. 6, a long round bar-shaped guide portion 18' is formed at the tip of the pulley support shaft 12,
Guide hole 17' on the side of cylinder body 20a
A guide portion 18' is fitted into the guide hole 17'. The abutment between the inner circumferential surface of the guide hole 17' and the outer circumferential surface of the guide portion 18' prevents the tension arm 11 from swinging in a direction perpendicular to its axis.

(3) In the embodiment shown in FIG.
1 is formed into a round bar shape and fits into the guide hole 17 of the bracket, and the nut 14 of the support shaft 12 is brought into contact with the side part 15b of the bracket 15.

(Effects of the invention) As explained above, according to the invention: (1) In the tension pulley device in which the tension arm 11 is supported by the support bracket 15 so as to be movable in the longitudinal direction, the tension arm 11
A steady rest guide mechanism (for example, the guide portion 18) that prevents vibration in a direction perpendicular to the axis of the bracket 1
5 or on the engine wall such as the cylinder body 20a, even if the drive pulley 1, fan pulley 2, and tension pulley 3 are misaligned due to manufacturing errors, the tension arm can be fixed by the regulating action of the guide part 18. 11 in the right angle direction, for example in the direction of arrow R in Fig. 1 or the arrow
Runout in the R' direction is reliably controlled. Therefore, an accident in which the tension pulley 3 becomes unable to rotate due to the bending of the arm 11 can be prevented.

Furthermore, since it is possible to prevent the tension arm 11 from swinging in the direction perpendicular to the axis, in the event of a belt breakage accident, the tension arm 11 can be reliably moved by the spring 24 and the engine can be stopped.

(2) Since the tension spring 24 is compressed between the spring receiving nut 22 and the bracket 15, and the belt can be tensioned only by operating the nut 22, the belt tensioning work is simplified.

(3) Place the initial tension setting stopper 25 between the spring receiving nut 22 and the bracket 15, and then tighten the nut 2.
2 until the nut 22 is locked with the stopper 25.
Since the spring 24 is compressed by tightening, the initial tension of the belt 5 can be easily and accurately set regardless of variations in belt length.

(4) Since the swing of the belt 5 that attempts to move in the direction of compressing the spring 24 is restricted by the action of the stopper 25, the swing of the belt 5 due to engine vibration is reduced, and the life of the belt 5 is extended.

(5) The part that moves integrally with the tension arm 11 is connected to the engine stop device via, for example, a wire, and the engine is stopped by the restoring force of the spring 24, so if the belt breaks, the engine stops automatically. The engine will stop immediately, preventing engine seizure.

(6) Tension arm 1 with pulley support shaft 12
1 is directly biased in the axial direction by a spring 24 to provide tension, which causes the pulley support shaft 1 to
2 can be shortened, and the bending action has little effect on the pulley support shaft itself.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a tension pulley device to which the present invention is applied (an enlarged cross-sectional view of Fig. 4), Fig. 2 is a view taken in the direction of the arrow in Fig. 1, and Fig. 3 is a view taken in the direction of the arrow in Fig. 1. 4 are front views of an engine equipped with the pulley device of FIG. 1, and FIGS. 5, 6, and 7 are longitudinal sectional views of different embodiments. 3... Tension pulley, 5... Fan belt, 11... Tension arm, 11a... Shaft bolt part, 15... Support bracket, 18... Guide part (an example of steady rest guide mechanism), 22... Spring retainer nut, 24...
Tension compression spring, 25... Stopper for initial tension setting, 33... Regulator lever (an example of engine stop device), 20a... Cylinder body.

Claims (1)

[Scope of utility model registration request] A pulley support shaft is fixed to the distal end side of a tension arm having a shaft bolt portion, the tension pulley is rotatably supported on the pulley support shaft, and the bolt shaft side portion of the tension arm is fixed to the support bracket with the shaft bolt. It is supported so that it can slide freely in the lengthwise direction, and a spring receiving nut is screwed into the shaft bolt part, and a compression spring for tension is compressed between the nut and the bracket to apply tension to the fan belt and to set the initial tension. Place a stopper, compress the spring with the nut until the nut is locked in the stopper, connect the part that moves integrally with the arm to the engine stopper, and when the belt breaks, the restoring force of the spring will stop the engine. An engine characterized in that a steady rest guide mechanism is provided on an engine wall such as a bracket or a cylinder body to prevent the pulley shaft side portion of the tension arm from swinging in a direction perpendicular to the axis. Tension pulley device for fan belt.